David Creed

Bio: David Creed is an academic researcher from University of Southern Mississippi. The author has contributed to research in topics: Quenching (fluorescence) & Chromophore. The author has an hindex of 18, co-authored 67 publications receiving 1232 citations.

The photophysics and photochemistry of the near-uv absorbing amino acids–ii. tyrosine and its simple derivatives

Abstract: — The photophysics and photochemistry of tryptophan and its simple derivatives is comprehensively reviewed with special emphasis on excitation by near-UV radiation. Topics explicitly discussed include the origins of large Stokes shifts in the fluorescence spectra, photoionization, the puzzle of multiple tryptophan fluorescence decay time, photochemical reactions in the presence and absence of oxygen, and the possible mechanisms of these reactions. A separate section reviews the photosensitizing properties of N-formylkynurenine, an important photooxidation product of tryptophan.

Water-Soluble Copolymers .40. Photophysical Studies of the Solution Behavior of Associative Pyrenesulfonamide-Labeled Polyacrylamides

Abstract: Copolymers of acrylamide containing less than 05 mol% N-[(1-pyrenylsulfonamido)ethyl]acrylamide were studied in aqueous solution The copolymer prepared by a surfactant technique was shown to possess some inherent blockiness or short runs of the pyrenesulfonamide label in dilute solution Intermolecular associations were observed above a critical concentration The copolymer prepared by solution polymerization showed random incorporation of the pyrenesulfonamide comonomer and no intermolecular association tendency over the concentration range studied

Light-induced shape-memory polymers

Abstract: Materials are said to show a shape-memory effect if they can be deformed and fixed into a temporary shape, and recover their original, permanent shape only on exposure to an external stimulus. Shape-memory polymers have received increasing attention because of their scientific and technological significance. In principle, a thermally induced shape-memory effect can be activated by an increase in temperature (also obtained by heating on exposure to an electrical current or light illumination). Several papers have described light-induced changes in the shape of polymers and gels, such as contraction, bending or volume changes. Here we report that polymers containing cinnamic groups can be deformed and fixed into pre-determined shapes--such as (but not exclusively) elongated films and tubes, arches or spirals--by ultraviolet light illumination. These new shapes are stable for long time periods, even when heated to 50 degrees C, and they can recover their original shape at ambient temperatures when exposed to ultraviolet light of a different wavelength. The ability of polymers to form different pre-determined temporary shapes and subsequently recover their original shape at ambient temperatures by remote light activation could lead to a variety of potential medical and other applications.

Principles of Fluorescence Spectroscopy, Third Edition

Abstract: This PDF file contains the editorial “Principles of Fluorescence Spectroscopy, Third Edition” for JBO Vol. 13 Issue 02

Protein aggregation and bioprocessing.

Abstract: Protein aggregation is a common issue encountered during manufacture of biotherapeutics. It is possible to influence the amount of aggregate produced during the cell culture and purification process by carefully controlling the environment (eg, media components) and implementing appro-priate strategies to minimize the extent of aggregation. Steps to remove aggregates have been successfully used at a manufacturing scale. Care should be taken when developing a process to monitor the compatibility of the equipment and process with the protein to ensure that potential aggregation is minimized.